Solid state components such as nematic liquid crystal (LCD) displays are often temperature-dependent in their normal operating characteristics. For example, an LCD display relies on the behavior characteristics of twisted nematic crystalline substances when these nematic crystalline substances are exposed to driving voltages. In response to such exposure to driving voltages, the nematic crystals tend to align themselves so as to provide a desired reflectivity of light. When such substances are arrayed in a pattern, different portions of the substances can be provided with different driving voltages, thereby creating a pattern. Because of the different characteristics of these substances at different temperatures, their performance becomes temperature sensitive.
In order to avoid such temperature sensitivity, heating circuits have been provided for such diplays. Prior art liquid crystal displays are provided with a backplane glass which is used as a supporting substrate for the liquid crystal display. In order to allow such displays to operate at low temperatures, a resistive layer of indium tin oxide (ITO) was placed on the back surface of the backplane glass. The backplane glass provided insulation between the ITO heater element and the liquid crystal display. Typically, the backplane glass was approximately 0.75 mm thick. This provided ample electrical insolation between the ITO heater and the LCD but also resulted in an extensive warm-up time. When tested at minus 54.degree. C., the LCD display required approximately 30 seconds warm-up time.
Full operation of a heating element inside an LCD display on the inside surface of the backplane, would cause deterioration of the liquid crystal substance. Therefore prior art heated LCDs had relied on external heaters, and the extended warm-up time.
This extended warm-up time was considered to be inadequate for some applications, such as for certain instrumentation on aircraft. It is therefore desired to provide a quicker warm-up time for the LCD. It is further desired that such a system for providing a quick warm-up time for an LCD not cause aberations in the normal performance of the LCD.